1. Field of the Invention
The present invention relates generally to docking and mooring systems for boats, more particularly, to a system which allows the mooring lines to substantially vary in effective length depending on the tide, wave action, wind or other factors.
2. Description of the Prior Art
Water is far from a stable surface. Tides, winds and waves rise and fall. When not in use, boats are normally attached or moored to a fixed object and allowed to float in the water. If simple mooring lines are used to attach a boat to a dock or in a slip, the combined actions of tide, wind and wave can injure the boat. If the lines are too taught, a rising or falling tide can stress the boat by pulling the boat above or below its natural level in the water. If, however, the lines are slack to allow for tides, wave and wind, these forces can slam the boat into its dock.
Various boat docking devices to prevent such damage are known and range in complexity from the use of floats to involved spring systems to counteract the forces of nature. These attempt to maintain the boat""s position by varying the mooring line""s effective length. For example, U.S. Pat. No. 5,694,879, issued on Dec. 9, 1997 to James Taylor, discloses a mooring device which is mounted between the dock and the boat. The line from the dock is attached to one end of a spring while the line from the boat is attached to the other end of a spring. Similarly, U.S. Pat. No. 4,022,450, issued to Smith, Jr. on May 10, 1977; U.S. Pat. No. 4,754,957, issued to Muttart on Jul. 5, 1988; U.S. Pat. No. 5,307,753, issued to Besonen, Sr., et al. on May 3, 1994; U.S. Pat. No. 5,450,808, issued to Beagan on Sep. 19, 1995; and U.S. Pat. 5,482,258, issued to Clauson on Jan. 9, 1996 disclose systems of one or more springs interposed between two lines, one from the boat to the device and one from the device to the dock. In each case the amount of play in the system is limited to the length of the spring movement. U.S. Pat. No. 5,749,535, issued to Kahn, III on May 12, 1998, discloses a piston and spring deceleration device for use with boat moorings where a traveling pulley is used to gain limited additional travel for the line. The traveling pulley movement is limited to the travel of the piston. Other methods for controlling the tension include the use of weights such as seen in U.S. Pat. No. 5,265,553 to Brydges, dated Nov. 30, 1993, or by floats as seen in U.S. Pat. No. 5,603 280, issued on Feb. 18, 1997 to Shackelford, Jr.; U.S. Pat. No. 5,716,249, issued on Feb. 10, 1998 to Dyhrberg. Here, travel is limited to the movement of the float or weight.
Each suffers from the same disability. The play in the mooring line is severely limited by the travel of the spring, float or weight as it responds to the load on the line. In other words, either the change in the effective length of the mooring line is small or the mooring system must be very large to accommodate corresponding large changes in the effective length of the mooring line.
The present invention is a boat mooring system for stabilizing a boat while docked which allows the effective length of the mooring line to vary for substantially greater distances than that of the prior art. The boat mooring system contains a multi pulley arrangement such that a small movement in a spring tensioning device results in a substantial change in the effective length of the mooring line. Thus, a change in tide, or weather conditions results in a substantial compensating effect.
To accomplish this desired result, one end of a spring is fixed in position at the first end of the device. A first floating pulley is attached to the other end of the spring. A first line is fixed at the second end of the device, opposite the first end of the device. The first line passes through the first floating pulley, then passes through a fixed pulley at the second end of the device and is then attached to and supports a second floating pulley. The mooring line from the boat passes through the second floating pulley, around a pulley fixed to the first end of the device and is then attached to the bottom of the second floating pulley.
The device is mounted in a closed case on pilings facing towards a dock or slip where the boat will be docked. The outer case of the device is made of a durable material which will not deteriorate when subject to drastic changes in the environment. Both upper and lower ends of the case are closed by solid plates. The front of the boat mooring system has an opening and guide to allow the second line to move freely in and out of the device.
The second line can be pulled from the device for attachment to the boat. The side of the boat opposite the pilings on which the device is mounted is fastened to a dock or a piling using a fixed line.
When the water level or weather conditions change, the pulleys and spring of the present invention will allow the rope to adjust its length according to the tension on the mooring line. The effective length of the line is not limited to the travel distance of the spring due to the pulley arrangement of the present invention.
Since the boat mooring system of the present invention is fixedly mounted on pilings, the boat need only carry conventional mooring lines. Different boats of different sizes, types and tonnage may use the same mooring system in the same slip. Unlike other mooring systems, the body of the present invention does not come in contact with the boat. This reduces the risk of damage to the boat.